Process of molding cement slabs



April 9, 1929. SMITH 1,708,555

PROCESS OF MOLDING CEMENT SLABS Filed March 9, 1927 '2 Sheets-Sheet 1 April 9, 1929. R. 0. SMITH PROCESS OF MOLDING CEMENT SLABS 2 Sheets-Sheet Filed March 9, 1927 Patented Apr. 9, 1929.

UNITED STATES ROBERT 0. SMITH, OF CHICAGO, ILLINOIS.

rnocnss or MOLDING CEMENT SLAIBS.

Application filed March 9, 1927.

This invention is directed to a process of making concrete slabs or sections in a single molding operation, with the sections con structed to embody highly desirablecharacteristics for building purposes.

The process is primarily directed to molding the respective sections in final form on a flat horizontal base, with the molding operation so carried out that the section when completed embodies an air space throughout the full length and height of the section; a substantial and appropriate metallic reinforce for the section, which reinforce is utilized in part as a means for interlocking adjacent sections together in wall formation; and a convenient ornamentation or variation of the outer surface of the section.

It is primarily intended that the section or slab molded according to the present proccss shall be equal in height to the height of a story of the building being erected and shall have a length preferably exceeding that of its height so that the building following the molding of the slabs may be quickly assembled, the peculiar and particular formation of the slabs adapting such for this ready and quick assemblage and interlocking to fori-n a firm, substantial structure.

The process also contemplates the molding in the particular slab or slabs of the necessary door or window openings and incorporating in such openings, during the process of molding, the necessary window and door frames for carrying these parts.

The process also contemplates the formation of a slab so that they may not only interlock one with "the other when assembled in wall formation but may also interlockwith superimposed slabs and with partition Walls and floors, both of which latter are molded substantially in accordance with the process of molding the slabs, so that through the slabs the entire building structure is interlocked and secured as a firm, substantial unit.

In order that the various steps of the proc ess may be better understood, the samewill be described with particular reference to the accompanying drawings, in which:

Figure 1 is a view of the molding unit, centrally broken out, and illustrating particu-' larly the reinforce formation and the means for forming the enlarged air chambers.

Figure 2 is an enlarged broken section through one end of the molding unit.

Figure 3 is a broken perspective view of one corner of the molded slab.

Serial .NO. 174,010.

slabs interlocked in angularly related posi tions.

Figure 7 is a vertical section showing the means for interlocking a floor section with the slabs. a

Figure 8 is a view similar to Figure 7, showing the use of a reinforce plate beneath the floor as required under some building reguw lations.

Figure 9 is a broken horizontal sectional, view illustrating the interlocking of the outer wall slabs and the inner wall or partition slabs. I

In carrying out theprocess, there is provided a platform 1 which may. if desired bebuilt of wood and laid on stringers 2. The platform is supported horizontally and of course is larger than the dimensions of the contemplated slab. Gauging strips 3 are placed on the platform in rectangular outline, defining an interior opening or platform space corresponding to the surface dimensions of the slab. These gauging strips 3, which will'be hereinafter termed the facing gauging strips, are comparatively thimand following the placing of these strips, a layer of concrete is placed on the foundation or platform within the outline of and substan outline form corresponding to the outline,

form of the facing gauges 3. Theseimolding gauges 5, 6 and 7 are ofa height correspond ing to the desired thickness of the slab above the facing layer 4i. This mold proper is provided with the various reinforcing andform ing elements for the slab, allof which are assembled between the gauges of the mold beforethelatter is applied in, molding position. The metallic reinforclngelements constitute longitudinally extending rods 8, trans-- verse rods 9 having their terminals hooked over the longitudinal rods, and vertical rods 10 disposed at the juncture of the'longitudinal and transverse rods with all rods at their junctures being connected by awire tie 11. The mold gauges 5, 6 and 7 are formed near their edges with inwardly projecting ribs 12 which not only form recesses in the slabbeing molded but are formed at appropriate inter vals with openings 13 in'which the ends of the longitudinal rods 8 and vertical rods 10 are placed and loosely held to assemble them with the mold and hold them in position during the application of the cement.

The cement slab of the present process is designed to present enlarged vertical chambers arranged at spaced intervals and extending throughout the full height of the V slab, and to provide for the molding of these chambers during the processof forming the slab, hollow inetiztllicbodies 14 of comparatively thin material and of approximately the shape illustrated in Figure 2 are loosely in serted through and held within openings 15 .in the top and bottom mold gauges 5 and 6.

These metallic bodies 141-, hereinafter termed molding shells,- have their upper and lower walls, as such shells appear in the molding operation, connected to central bars 16 through a series of links 17 pivotally connected to the shell walls and to the bars. Through obvious endwise movement of'the bars, the shells are collapsed to an extent to permit their convenient removal after the setting or partial setting of the cement.

In the slab of the present process it is important in order to permit the slabs to be interlocked in wall formation, to provide recesses in, the end walls of'the slabs. To secure these recesses during the'n'iolding'operation,

the end mold gauges 7 are each provided with a sheet metal form 18. These forms are of V-form in cross section with their marginal edges'secured to the mold gauges and the converging'walls extending inwardly from said gauges to form the desired recess intheslab. The means whereby the adjacent slabs may be interlocked extends into this recess, and to provide for such, V-shaped reinforce bars 19 i are terminally connected to the juncture of To permit the lowermost set-of reinforcing rods orlaid rectly upon the facing layer 4 before the mold proper is applied; Cement is then poured into the mold for substantially one-half the depththereof, that is to the line 22, Figure .2, this cement of course filling the space below the molding shells 14. The slots 20 in the sheet metal forms 18 may be temporarily covered by a sheet of tar paper or the liketo prevent the cement from passing therethrotigh. To the extent completed, the cement partially encircles the moldingshells,

and at this point an appropriate layer of readily separable material, as sand, sawdust orthe like, is la1d upon the upper surface of the cement. This layer, indicated at 23,1s applied over the entire cement surface presented when the mold is half filled. The mold is thereafter-filled with cement up to and somewhat above the upper layer'of reinforce rods, a sheet of'gauze or the like 24, similar to the sheet 21, being-laid upon or secured tothe upperlayer of reinforce rods so to be embedded in the cement. The upper surfaceof vthe slab as molded, preferably constituting the outer surface of the slab as erected in the wall,'1s then apphed, the materialbeing used being of'a well known water-proof character ordinarily"utilized as a facing strip for cement structures. 'Thisfinal facing being fully op'en to the workman may be readily ornamentedv in any desired or well known manner, it being apparent that by reason of 7 its convenientdisposition any desired type of ornamentation may be'carried out Thus, for example, Independent ornamental molds may be arranged and after the facing layer has been partially'set, suchmolds maybe removed and contrastingly colored material ap plied in the molded outline, the full face or any portion of the facing strip may be supplied'with pebbles or marble'chips, or in fact any type of ornamentation desired may be carried out. f I

The described molding operationis that.

of an ordinary wall slab without openings,

and it is of course'understood that certain of theslabs will have window or door openings, and as it is a purposeof the present invention tofprovide a process in which the slabs are molded as a unit, provisionis also made for similarly molding slabs containing openings. In Figure 1 the-re is illustrated the molding of a slab containing a window opening, the 5'- process utilized in such molding being the same for any other desired opening. In providing for a window or door opening, a rectangular molding frame 25 is positioned on the base or platform 1 at the point desired for r the opening. .In providingfor a window opening, this frame'25 will be such as to position the window frame about centrally of the thickness of theslab, whilein providing for a door opening. the frame will be of less height so that the door frame will be positioned more closely to one of the faces of the slab than to the other. After the frame 25 has been applied, a window frame 26 is positioned thereon and the concrete pouring op eration carried out before described. For the final half of the concrete pouring operation, a molding frame 27 is arranged upon the window frame 26 to maintain the window opening. The relatively outer surfaces 28 and 29 of the molding frames 25 and 27 are of course of such shape as to give the desired slope, curvature or ornamentation to the cement surface inwardly and outwardly of the window or door frame. This ornamentation or surface characteristic may be of any desired character, such not being important to the present process. As the window or door frame is somewhat greater in its overall dimensions than the similar dimensions of the molding frames 25 and 27 it is apparent that such window or door frame will be embedded in and firmly held by the cement of the slab when the latter is set. Preferably, the window or door frames are of metal to avoid the use of wood in the structure and to further avoid the shrinking of the wood from the cement.

As finally completed, the slab indicated at 30 isformed with end channels 31 of V-form into which project interlocking reinforce rod sections 32, which are parts of the reinforce bars 19, the slab having vertically extending air chambers 33 as defined by the shells 14:, with these chambers communicating with each other and with the end channels 31v by narrow channels 34. It is understood that after molding. the cement slab is allowed to set for two or three days and is then, after removal of the molding gauges, turned up on end, that is into the position it will assume in the wall, and allowed to thoroughly cure, this requiring probably two or three weeks.

As before stated, the unit slabs are of a height approximating the height of the story of a building and preferably of a length commensurate with the length of a room in the building. In assembling the slabs in wall formation, the slabs are arranged in longitudinal alignment and for the temporary insuring of such, small blocks may be placed in the vertical channels 35 of the slabs formed by the ribs 12 on the end gauges 7 The slabs may be conveniently handled by a hoisting derrick or the like, the interlocking reinforce projections 32 conveniently serving for attaching the lifting means. When arranged in longitudinal alignment, the end recesses 31 of the slabs are in registry and the interlocking reinforce projections. 32 in alignment and close proximity. Metallic clips 36 are forced over the immediately adjacent interlocking reinforces of the respective slabs throughout the height of the slabs, following which the blocks in channels 35 may be removed and the registering channels 35 of the respective slabs filled with cement. The slabs are thus interlocked and firmly fixedtogether.

The identical operation is carried out where the slabs meet at an angle, as at any corner formation; This arrangement is. illustrated in Figue 6, the sole requirement being that the slab constituting the corner slab, here indicated at 37, isformed with a recess 38 corresponding to the recess 31 in the unit slabs, in one face of the slab rather than the end. This formation does not vary the process and merely means that the sheet metal form 18 be arranged in the moldon the platform 1 instead of on the end gauge 7 V i In arranging to support the floors, it is t be understood that such floors, which may be molded in outline form similar to that of the slabs, though preferably without the communicating openings 23 between the air channels, are arranged on the upper edges of the slabs forming the particular story being erected. The floors indicated at 39 are formed by the use ofmolding shells with longitudinally extending air channels 40 and are further formednear their edges by appropriate ribs on the molding gauges with narrow channels 41. These floors are laid'on the upper ends of the slabs so that the extreme ends of the floors extend to a point substantially mid-length the width of the upper ends of the slabs. That is to say, the floor covers substantially one-half the Width of the air chambers 33 and the communicating channels 34. Before applying the floors, cement mortar is placed in the longitudinal channels a2 in the upper ends of the slabs, which channels have been formed .by the ribs 12 on the end gauges 7 of the mold, so that when the floor is applied this cement extends into the channels 41 in the floor and holds the latter in place. To accommodate the floor, the slabs forming the next story above the floor are formed with a recess 43 from their inner surfaces corresponding to the thickness of the floor, this recess being provided for by laying a section ormold strip on the base 1=of ap propriate form and size, as will be readily understood.

Where it is required by building regulations that the floor; he additionally supported, the arrangement lends itself to the utilization of a .meallic plate i lto be placed upon the upper ends of the slabs supporting the floor and having headed bolts 45 to extend into the longitudinal channels 4-2 of the slabs and 41 of the floor. The channels being filled with cement prior to the application of the floor or plate, such cement whensetting around the heads of the bolts will firmly secure all parts in applied position.

The slab constructed according to the present process readily lends itself to interlocking with partition walls indicated at 46 in Figure 9. These partitionwalls are molded similar to the slabs, having the air channels. 47, in-

V tercommunic-ating channels48, end recesses channels '51; The main slabs where'utilized to interlock with a'partition Wall have the interlocking channels 31 extendedto the inner face ofthe slab, as at 52, 'Figure 9. This merely. requires that the metallic'form 18, instead ofbein'g of true V-form, will, asarranged in the: mold, have its outer margin inclined and its innerlength extended in parallelism to the adjacent end gauge 7 of the mold. The partition wall 46 is aligned with the main slabs and at right angles thereto, with the edge channels 51 of the partition and slab in registry. A three-prong connector 53 is then applied to the interlocking reinforces of the two aligned main slabs andof the partition wall 46. This connector is formed to draw the parts together and firmly interlock them, and with the connectors applied to all sets of horizontally aligned interlocking brace rods, the partition wall is firmly fixed to the main slabs. The channels 51 may be thereafter filled with cement to further bond the parts. As previously stated, after molding, the slabs are allowed to set and are then placed 'on end untilcured. During the curing oper ation, a layer of sand or sawdust 23 formed between the'air chambers of the slabs will,

dry and fallout. This leaves a clear uninterruptedchannelbetween the air chambers and between the end air chambers and the end tition walls. Furthermore, as the floors only occupy one-half the Width of the slab, it is apparent that the vertical air chambers and openings in the slabs are not completely 1nterrupted by the floors, so that the full outer wall of the building as well as the partition walls, while made up of slabs of a unitary structure, are nevertheless of two complete, wholly. separated walls, andthere is an uninterrupted and continuous air space throughout the full height and length of the building and through all the partition walls. This obviouslytends to a'damp-proof Wall and partition and further tends to an effective insulation against the passage'of heat or cold. This result is, secured in a single molding operation of the respective units, requiring no further reconstruction following such molding It may be found that the concreteor cement will adhere to the shells 14 and in order to prevent this and facilitate the removal of ings, the air chambers therein produced by the shells Mare continuedin the slababove and below such openings, as indicated in V dotted lines in Figure 4. This is readily provided for by using shells 1 L otappropriate length and blocking off the ends next: the

openings in any appropriate manner as by a sheet of metaliornthenlikc. a

structed, and any and all other uses for which the construction may be found to'be adapted. TlHS applicatlon is a continuation in part of my application filed December '5, 1923,"

Serial No. 678,675, whichapplication has issued as Patent No. 1,673,760, and from which applicationthe process herein. described was divided. i

What I claim to; be new is:

1. A method of molding concrete slabs and' the like, consisting in providing a base, arranging thereon facing gauge strips of a height'cquallin g a facing layer of the slab, V

filling the space within such facing gauge strips with material, placinga molding element on the facegauge-strip, applying a me tallic reinforce for the slab to saidniolding element, applying material within the molding element to substantially one-half the height thereof, covering the surface of such molded material for an appreciable thickness with material capable ofseparating from the slab after the latter is'dried, and thereafter filling, the remainder ofthe'molding element with material, allowing the material to set, removing the moldingelement, and arranging the slab on end for curing.

2. A process of molding concreteslabs -for building purposes, consisting in molding a surface layer-of the slab, providing a mold to complete the slab with said mold supporting a metallic reinforce and hollow shells to form a vertical air chambers in the slab, molding the slab within suchmold to substantially one-half its thickness, applying a layer of material on the molded portionwhich will separate from tlie'slab when the latteris set,

,completing'the melding of tlie'slab, and removing the moldjwithout disturbing the reinforce. i

p 3; A method of moldingconcretei slabs for building purposes, consisting in 'providinga base on which the slab is molded, arranging on the base a series-of molding strips to do termine the lengtln-breadth and thickness of the slab, utilizing the molding strips as a support for the reinforcement for the slab, providing certain of the moldin strips'with a molding shell to provide recessesinvtlie,

surface of the slab and extending certain parts of the reinforcement into said molding shells, molding the slab Within the molding strips to thereby form recesses in the slab with the extended reinforcement projecting into said recesses to provide a means for interlocking adjacent slabs.

4;. An apparatus for molding slabs of concrete for building purposes, comprising a base, comparatively thin end and side gauges arranged onthe base to define a thin layer of material for the slab, and a molding element made up of end and side molding strips to be superimposedon said thin gauges, a slab reinforcement removably carried by and held in position by said molding strips, and molding shells carried by the molding strips to provide longitudinally extending air chambers in the completed slab.

5. An apparatus for molding slabs of concrete for building purposes, comprising a base, comparatively thin end and side gauges arranged on the base to define a thin layer of material for the slab, and a molding element made up of end and side molding strips to be superimposed on said thin gauges, a slab reinforcement removably carried by and held in position by said molding strips, molding shells carried by the molding strips to provide longitudinally extending air chambers in the completed slab, and molding forms carried by the molding strips to form recesses in the completed slab, certain parts of the slab reinforcement extending into said molding forms to present projections in the slab recesses When molded.

In testimony whereof I aflix my signature.

ROBERT 0. SMITH. 

